Process of producing soap



Patented Dec. 17, 1940 UNITED STATES PATENT OFFICE 2,224,985 rnocsss or PRODUCING SOAP No Drawing. Application February 23, 1938, Serial No. 192,184

Claims.

The present invention relates to an improved soap composition and the method of producing the soap from marine oils.

A principal object of the invention is the treat- 5 ment of a marine oil such as sardine, menhaden or herring to produce therefrom a special fatty acid composition which is converted into a soap having superior detergent characteristics.

An additional object'of the invention is the production of a special ClB fatty acid-containing composition from marine fatty acids which includes the elimination of C20 and C22 acids, and saponification of the special fatty acid composition to produce a soap at least as good as the soaps obtained from selected vegetableand animal oils.

Still another object of the invention is to separate from a hydrolyzed marine oil a special fatty acid composition which is substantially free of C20 and C22 unsaturated acids, thereafter partially hydrogenating the remaining fraction,v

and converting the hydrogenated composition into soap.

These and other objects will be recognized upon 25 a consideration of the following description of a preferred embodiment of the invention.

The marine oils consist ofcomplex mixtures of triglycerides containing nine or more different fatty acid radicals. As marine oils are a relatively cheap source of triglycerides they have been employed to some extent heretofore in admixture with other fatty acids and glycerides for soap making purposes. However, the nature of the complex marine fatty acids is such that there is 35 a limit to which they may be used in a soap mixture. The reason for this limitation is that the fish oil fatty acids have poor detergent characteristics. If too great a quantity of ordinary mixed fish oil fatty acids 'or fish oil is employed in admixture with other fatty acids in producing soap, the detergent characteristics of the soap will be so poor as to make the product undesirable. Furthermore, the fish oil or fatty acids impart to the soap 9. fish-like odor unless hydrogenated. In accordance with the present invention fish oil fatty acids are treated in such a manner as to produce therefrom a special fatty acid composition which may be used to form a soap of im- 50 proved detergent characteristics and with which it is not necessary to incorporate other triglycerides or fatty acid fractions from vegetable or animal oils. Thus, from a relatively cheap material which has been recognized as being inferior u in the production of soap, there is produced in accordance with the present invention a soap which is of superior characteristics.

In the production of the improved soapcomposition a marine oil such as sardine oil is subjected to a hydrolyzation or splitting operation, '6 as by the Twitchell process, to produce'a complex fatty acid mixture and glycerine water. The glycerine water is separated from the fatty acid and the resulting fatty acid mixture, which may contain a small quantity of unsplit triglycerides, 1 is subjected to a separation operation as described in our copending application Serial No. 96,732, filed August 19, 1936, of which the present application is a continuation in part. In this process of separation by fractional distillation 5 the fatty acid mixture is subjected to a continuous heating step in admixture with steam to raise the temperature of the fatty acids at least as high as is necessary for their vaporization under reduced pressure. The heated fatty acids and 20 steam mixture are flashed into a vaporization or expansion zone and subsequently are passed upwardly through a series of pools of previously condensed fatty acids having successively decreasing boiling points. The low boiling fatty acids at the top of this series of zones are condensed and in part returned to the zones to provide reflux liquid.

The conditions of the fractionating process such as temperature, pressure, steam and reflux are controlled so as to provide a bottom fraction which contains substantially all of the C20 and higher carbon chain fatty acids contained in the original mixture. Steam generally is passed upwardly through the series of pools of fatty acids to assist in the fractional distillation of the fatty acids.

By properly controlling the operating conditions of the process, which includes control of 40 the heating, the quantity of steam employed in theprocess, the amount of reflux, the number of zones and the absolute pressure maintained therein, there may be effected a separation from the fatty acids of long carbon chain fatty acids having 20 or more carbon atoms; These C20 and C22 fatty acids generally are highly unsaturated and may contain two or more double bonds. When C20 and higher carbon chain fatty acids are eliminated, the remaining portion ofthe fatty characteristics, as in the case of the whole fatty acid mixture.

The special Cwfatty acid-containing composition resulting. from the elimination of the C20 and C22 fatty acids is converted into soap by the usual method of saponification with an alkali such as sodium hydroxide.

In one example of the operation of the process sardine oil was split and the resulting fatty acid mixture was subjected to fractional distillation by the process described. The operative factors of' the fractionation process were controlled so that about 5 per cent of the fatty acid mixture was taken off as a low boiling overhead product. The next fraction separated comprised about 55 per cent of the feed stock having a distillation temperature below 210 C. at 5 mm. pressure. The special fraction has practically no fish odor and contains substantially no fatty acids having more than 18 carbon atoms. In addition to this intermediate product the process resulted in a residual C20 and C22 fatty acid-containing fraction and a quantity of neutral oil.

The special C13 fatty acid composition separated as described will have an iodine value which may range from 75 to 105, depending upon the particular fish oil which is used. There may be aslight residual-odor in the material and if this is'the case it is possible to:subject the special fraction to'a hydrogenation procedure prior to saponification. A slight hydrogenation generally a is sufiicient to render the C18 fatty acid composition odor-free, although further hydrogenation may be effected if desired. This hydrogenation has the effect of producing'a harder fatty acid mixture. 'The iodine value after the hydrogena- .tion procedure is completed will depend upon the extent of the hydrogenation procedure.

The fatty acid composition obtained by the fractional distillation of the mixture of fatty acids resulting from the hydrolysis of fish or marine oils will have an acid value of not less than 210 and will be substantially free of fatty acids containing more than 18 carbon atoms. It is preferred that the iodine value of the special fraction not exceed 110. In a hydrolyzed fatty acid mixture obtained from splitting of fish oils the complex mixture will contain a substantial.

percentage of C20 and C22 fatty acids. The fractionation procedure is controlled so that in the intermediate product obtained for the production of soap in accordance with the present in- Soa 'irom Soap irom spec l fish fatty acid gg g f fraction Detergentrating l 5 Rate of solubility at 110 F. .peroent 89 47 Suds:

1 minute .inches 9}; 1% 5 minutes ..d0 12% 2% 10 minutes do Over 14 3 The detergent rating noted above is based on a wash test in which carded wool is soiled in a standardized manner and washed under standa'rdized conditions in a Thor household cylindertype washing machine. A rating of 1 is excellent while a rating of 5 is quite poor. The suds tests are made by measuring the height of the suds on a rod attached to the Thor washing machine. To obtain the rate of solubility factors the percentage of soap dissolved by stirring in a definite volume of water under standardized conditions for a definite length of time is measured. The percentage figures in the table indicate the rate of solubility.

The special fatty acids fraction produces a better soap from the standpoints of detergent characteristics and sudsing than soap produced from hydrogenated fish oils, or from the rejected fish fatty acid fractions from which the desired composition is obtained, or from either of these materials partially hydrogenated.

There is no limit as to the quantity or percentages of the special fish oil fatty acid fractions which can be employed in producing a soap of highly desirable characteristics. The special composition may be employed alone or in some cases it-will be found desirable to combine it with fatty acids obtained from other oils such as vegetable or animal oils. In fact, if it is desired to enhance the detergent characteristics of various vegetable and animal oils, this may be done by employing the special fish oil Cm fatty acid fractions. The rejected fractions of the fish oil fatty acids may be put to other desirable uses than soap making, so that there is no waste product in the process. As the special fatty acid fish oil fraction is more desirable in the production of soap than are ordinary fatty acids obtained from vegetable and animal oils, the special composition may be sold at a price at least equal to the price of vegetable and animal fatty acids, and generally it is possible to obtain a better price. An oleaginous product which prior to the present invention has had limited sales value and limited application in soap making is converted in accordance with the invention into a product which is even superior in characteristics to the products knownheretofore.

It will be recognized thatthe particular composition of the special 01a fish oil fatty acid-containing fraction may be varied considerably without departing from the scope of the invention.

We claim:

1. A process of producing soap, which comprises subjecting marine oils to hydrolysis to produce a fatty acid mixture, subjecting the fatty acid mixture to a fractional distillation procedure to produce a special C13 fatty acid-containing composition containing less than 3 per cent C20 and C22 fatty acids, controlling the operative factors of the fractional distillation to produce said special composition having a boiling point below 210 C. at 5 mm. absolute pressure, and subjecting said special fatty acid composition to saponification.

2. The process of producing a soap, which comprises hydrolyzing a marine oil to produce a fatty acid mixture, subjecting said mixture to a fractional distillation procedure to separate a special Cu; fatty acid-containing composition containing less than 3 per cent C20 and C22 fatty acids, and having an iodine number from to 105, and a distillation temperature below 210 C. at 5 mm. absolute pressure, and subjecting said special fatty acid composition to saponification.

3. The process of producing soap, which com-- prises subjecting a fish oil to hydrolysis to produce a fatty acid mixture, subjecting the mixture to a heating operation, introducing the heated materials into a distillation and expansion zone of reduced pressure, passing the heated vapors upwardly through heat exchanging zones of condensed fatty acid mixtures having successively lower boiling points, and returning to the upper portion of said zone a suflicient quantity of condensed low boiling fatty acid as reflux to produce in an intermediate zone a C18 "fatty acidcontaining composition containing less than 3 per cent C20 and C22 fatty acids, and subjecting said mixture to saponification. c

4. The process of producing soap, which comprises subjecting a marine oil to a splitting operation to convert a major portion of the oil into free fatty acids, subjecting the split product to a fractional distillation procedure in which low boiling fatty acids are returned as reflux and therein recovered a Cu fatty acid-containing intermediate product containing less than 3 per cent C20 and higher carbon chain fatty acids, said product boiling below 210 C. at 5 mm. absolute pressure and having an iodine value ranging from '75 to 105, and saponifying said product.

5. The process of making soap, which comprises hydrolyzing a marine oil to produce a fatty acid mixture, fractionally distilling the mixture, controlling the operating conditions of the fractional distillation procedure to produce a Cu marine oil fatty acid-containing fraction containing less than 3 percent of C20 and C2: fatty acids, subjecting saidfraction to hydrogenation, and saponifying said fraction. i

, RALPH H. POI'IS.

JOHN E. McKEE. 

